The steam-water separators mounted on a horizontal deck within the upper steam drum of a generator have a well-known structure. The drum functions as a header for the multiple tubes of the evaporative circuit including the waterwall of the furnace, receiving from the tubes a mixture of saturated water and steam as the mixture flows upward from its heat absorption in the evaporative circuit. A fundamental requirement is to separate this mixture into its relatively dry steam and its unvaporized water. Separated, dry steam is drawn to usage, generally in a turbine, while the saturated water is recirculated to absorb additional furnace heat in the tubes of the waterwalls. Thus, the steam drum forms an important fork in the road over which flows the mixture of steam and saturated water. At this juncture in the road/path, static separation structure is mounted to receive the mixture and positively separate it into its components.
In advancement of this separation art, little notice is given to the source of heat vaporizing some portion of the feedwater. The source of heat may be by nuclear fission, the combustion of pulverized solid fuel, oil or gas combustion, etc. All these fuel sources produce heat absorbed by feedwater in tubes which route partially vaporized feedwater up to the steam drum. Separated, the saturated water forms a lower body in the horizontally extended drum which interfaces with steam collected in the upper region of the same drum. A horizontal plate or deck is mounted within the drum as a support for the steam-water separators and holes through this deck form passages for the upwardly-flowing steam and water mixture. The steam is drawn from the drum with a conduit connected through the upper wall, while the feedwater is drawn through conduits connected through the lower wall of the drum. The separator structures are mounted over the holes through the horizontal deck where they work their technological magic in wringing out the steam from saturated water. The saturated water constantly flows downward from the structure, while the steam separated therefrom flows upward.
The primary separation of the steam from the saturated water takes place within the cylindrical, open-ended shells vertically mounted over the holes of the horizontal deck. The upwardly-flowing steam-water mixture is spun toward the walls of the shells, causing a primary separation as the heavier water flows horizontally outward from the spinning mixture, leaving the lighter steam to travel up the center of the whirling mass. Of course, the primary separation is far from ideal and secondary separation is carried out on both the steam entraining finer bodies of liquid and on the saturated water containing residual droplets of steam.
Additional spinning of the primarily separated saturated water has been carried out as disclosed in at least Carson U.S. Pat. No. 4,162,150. In this disclosure the primarily separated saturated water flowed downwardly in the annulus between two cylindrical shells has been given a second spinning with an object to releasing remnant steam. If this saturated water skimmed from primary separation can be alternatively flowed over a surface to form thin sheets, the bubbles of steam entrained in the saturated water can be provided shortened paths to the freedom of separation.